President Barack Obama has brought Vice President Joe Biden to tears, presenting him the nation's highest civilian honour - the Presidential Medal of Freedom.

Mr Biden, 74, was visibly overcome with emotion as the president, in his last days in office, surprised him with the prestigious award.

In remarks billed as a joint farewell to family, friends and staff before they leave the White House next week, Mr Obama addressed Mr Biden as his "brother" and described him as "the finest vice president we have ever seen" and a "lion of American history".

"For your faith in your fellow Americans, for your love of country and for your lifetime of service that will endure through the generations, I'd like to ask the military aide to join us on stage," Mr Obama said during the ceremony at the White House.

"For my final time as president, I am pleased to award our nation's highest civilian honor, the Presidential Medal of Freedom."

President Barack Obama presents Vice President Joe Biden with the Presidential Medal of Freedom during a ceremony in the State Dining Room of the White House in Washington. (AAP) ()

Mr Biden's jaw dropped and he turned his face away from the audience to wipe away the tears.

"My first and only time I will bestow this medal with an additional level of veneration, an honour my three most recent successors reserved for only three others Pope John Paul II, President Ronald Reagan, General Colin Powell," Mr Obama continued, as Mr Biden took deep breaths.